Pattern positioning device



June 22, 1954 1 A, STROMMEN 2,681,484 A PATTERN POSITIONING DEVICE FiledJan. 14, 1952 2 sheets-sheet 1 June 22, 1954 J. A. sTRoMMEN 2,681,484

' PATTERN PosIToNING DEyIE Filed Jn. 14, 1952 2 sheets-sheet 2 D MW m:12f-

,axwmw Patented June 22, 1954 STATES FiiiiffENT OFFICE PATTERN PsfiimoDEVICE John .A. Strommen, Milwaukee, 'Wis., assigner to Allis-Chalmers-Manufacturing Company, .Mil-

.ApplicationiJanuaryl14, 1952, Serial No. 266,396

I Claims. l vThis invention relates Ato molding apparatus and ismoreparticularly conoernedWith-.the provision of apparatus foreiectively'utilizing a pattern segment in the formation of molds.

AIn oneof its aspectso the present invention is of .particularadvantage, although :not Vin `any manner limited, in the production ofannular molds. `Annular `molds vhave heretofore been made `by usingasegmental pattern and rotating it aroundits center -insteps,fsand beinglpacked against the circumferential outer surface of the pattern at-eachsten This type of pattern has previously been made iup of at leasttwoseparate parts, .so assembled that manual removal of onel part, which.is usually in the nature of a wedge, vis necessary before the otherpartcan be withdrawn. from the mold. i Insertion. of the wedge functionsto correctly position the other part of the pattern in a .predeterminedrelation to a surrounding mold .ask or other `suitable structure.

`'Ihecost involved in using Vpatterns comprising complementary parts, atleastone of rwhich is a wedge, is excessive because al completely newpattern comprising thetwo-parts is required foreach mold having a.materially different diameter.

Moreover, Wedge parts which are usually Adri-ven into place, soonbeccmewdamaged or Worn sufficiently to requireffrequent replacement. In.addition, a high degree of `sltill and considerable effort .are`required rin effectively .utilizing .such patterns andconsequently.thelabor costis high.

`The presentinvention has as anobject to prov'ide yapparatus "foreffectively .utilizing` a pattern segment in an improved-mannerminimizing the time, eiort and skill necessary Vfor thefproduction ofsatisfactory molds.

Another object of this invention is the` provision of 'apparatus foreiectively positioning and manipulating pattern segments `of differentsizes Wheibykthe cost ofproviding patterns for molds of different`dimensions is greatly reduced, in that Aonlyxthe unitary patternsegment'need be changed;

'Stillanother ob'je'ct of the presentinvention is "the provision ofapparatus "of theforegoing type whichaffords the advantage ofbeingfoolproofin operation, which .is `simple and inexpensiveto 'constructandmaintain, andwhichaffords readyadjustment of the" position of 'a patternsegment associated therewith.

' Other objects andadvantages will appear from the `following'descriptiontofa structure'illustratng an embodiment of .the invention,reference being hadto .the accompanying drawings, in which:

Aiiigl isa-'topwewp'f an apparatus embodying i2 the invention with apattern segment disposed :in its mold forming position;

Fig. `2 isa top View lsimilar `to Fig. `l 'showing thepattern segment4in its .innermost position relative to the mold;

Fig. 3 lis a top view `similar to Fig. :2 showing the position of thepattern segment after counterclockwise rotation of the same throughanangle of nearly- Fig. 4 is a top view similar to Fig.3 showing thepattern segment .disposed-in its next .mold forming position;

5 is a vertical section taken `along line V-V of Fig. 4;

Fig. 6 is a vertical section taken `along lline VI--VI of Fig. 3;

Fig. 7 is an enlarged topview similar -to Fig. 1 with the flask omittedin the interest of clarity and with thepattern segment shown as anintegral part of a hub portion o1" the pattern moving mechanism;

Fig. 8 is anxenlarged top-view similar toEig. 7 with the pattern shownin its innermost `position in conformity with Fig. 2;

Fig. 9 is a vertical section taken along the line XI-XI of Fig.eiwiththe wrench and aportion of the patternsegment omitted in theinterest ofclarity; and

Fig. l0 is a schematicdiagram showingessential coacting parts of thepattern positioningapparatus in proper Working position.

As shown in the drawings, an apparatus embodying the invention comprisesan arcuate pattern segment -I rigidly secured `to a split hub memberZ,whichis `held together by bolts-3 and nuts 4` which coactwith Bangeportions ofsaid split hub. It is usually `preferableto detachably securesegment I tosplithubmember `2` by any suitable means, which isdesignated generally by the numeral V5. An eccentric collar 6 isjournaled forrotationin splithub `2,.and is Yrotatably ldisposed on averticalfspindle -1 which is rigidlysupported ina .spindle receptacle.Receptacle `Il is xedlysecured `to amoldboard` or other suitable surface9 forming the bottom .ofv flask I I. Eccentric collar Sais provided withapairwofrecesses. I2 inits outer surface, which areadapted toreceivecomplementary projections on a-special collar .rotating wrench I 3 `asshownin Figs. .7 and'.

A collar stoppeg I4.is rigidly xed infsplit.' hub 2 so that itiscoactable with theopposite ends or shoulderportions I6 of a`protru'dinglange I1 on collar'li, as best shown in .Figs. V'7 and-:8.Items I4, I'E and I'I maybe consideredasmeans for'limiting rotation ofcollar 6 relative to hub 2.

.n since the rotational limits of collar 6 relative to split hub 2 arereached when one or the other of ends I5 of flange I'I engages stop pegI4. The eccentric collar is provided with a lip portion i 3, whichcoacts with split hub 2 and prevents eccentric collar 6 from slipping,in response to gravity, through split hub 2 and out of Contact with it.

In operation, the entire assembly, which comprises the elements I, 2, 6,7, and associated parts, is centrally disposed in the flask I I, andeccentric collar 6 is rotated to place pattern segment I in its maximumradially outward position as governed by the coaction of flange Il andstop peg Ill. Y

While the assembly aforementioned is in this position, side boards I9are placed against the edge of pattern l and pushed radially outwardagainst the inner surface of flask cheek 2 l Next, molding material ispacked in the space defined by the outer peripheral surface of patternl, the

inner surface of ilask cheek 2l, and the side boards I9. After thispacking operation is completed, side boards I9 are removed, andeccentric collar Ei is preferably rotated to its maximum radially inwardposition, which in the case of the present invention is 135. Thispositions the apparatus as shown by Fig. 2.

If desired, a smaller angular rotation is permissible, this beingdetermined by the amount of clearance which must be provided between thepattern and the mold in order to conveniently allow for rotation of thepattern. When using a 90 pattern segment, the collar t should be 45 fromthe position it would be in if it were to have its thickest or maximumeccentric portion between its center of rotation and the circumferentialmidpoint of the pattern segment against which molding material is to bepacked. This positioning insures that the pattern segment will not bejammed into the packed molding sand as the eccentric collar is rotatedto cause withdrawal of the pattern segment. Assume collar 6 initiallypositioned so that its maximumY eccentric portion is between the centerof rotation ofthe collar and the circumferential midpoint of the patternsegment. When the eccentric collar is `rotated from its initial positioncountercloclf.- wise to cause withdrawal of the pattern segment, theedge of the pattern segment adjacent the radial edge B, as shown in Fig.l0, will move to the left at a faster rate than it will withdrawinwardly and it will be jammed into the packed molding sand damaging themold. Damage to the mold can be obviated by designing the patternsegment so that the circumference of the pattern segment is concentricto the periphery of flask II when the thickest portion of collar 6 is atleast 45 from the position it would be in if its thickest portion werebetween its center of rotation and the circumferential midpoint of thepattern segment. This allows the edge of the pattern segment adjacent tothe radial edge B to move inward at a faster rate than to the left whenthe eccentric collar is rotated to cause withdrawal. As a result, thepattern segment is cleanly withdrawn from the mold surface withoutdamaging it. In Fig. 10, the circumference of pattern segment I isconcentric to center pointF and therefore concentric to the periphery ofany flask having a center of arc at point F, although the thickestportion of collar 6 is located at point A. Generally, if a patternsegment covering more or less than 90 is to be used, the ecentric collar6 can be allowed to approach no closer to its full radially outward CADposition than half the number of degrees covered by the pattern segment.

Next the pattern and its associated assembly is rotated in iiask IIaround spindle 7. The extent of this rotation is preferably slightlyless than the number of degrees covered by the pattern segment so as toeffect an overlapping of the pattern with the previously packed moldingmaterial as shown in Figs. 3 and 6. When this has been done, eccentriccollar E is rotated to a maximum radially outward position governed bythe coaction of flange I'I and stop peg I4. One side board i9 is placedagainst the open edge of pattern I and pushed radially outward againstthe inner surface of ask cheek 2|, after which sand is packed in thespace between pattern I, flask cheek 2i, side board I9, and that part ofthe mold previously formed in the rst operation. This results in anarrangement of the apparatus such as shown in Figs. 4 and 5.

The steps just described are repeated until pattern segment I has made acomplete revolution around spindle 'I and a circular mold has beenformed in iiask II. This completes the formation of a circular mold suchas is indicated in the drawings, whereafter the flask and mold formingapparatus arerremoved as desired.

In Fig. 10, the pattern segment I is shown in its ramming position withthe point of maximum eccentricity A on collar 6 disposed in radialalignment with the true center of rotation F of pattern segment l and aselected radial edge B of the segment. Obviously the point of minimumeccentricity C on collar 6 will always be spaced 180o from the point ofmaximum eccentricity A. The other radial edge D of pattern segment I isspaced X in a counterclockwise direction from the point of minimumeccentricity C on collar 6. Consequently collar 5 can be rotated 2X in acounterclockwise direction from the position shown in Fig. 10 withouteffecting any change in the angular position of segment l. That this isso is obvious, when it is considered that during rotation through anangle of XQ in this direction from the position shown, radial edge Dwill move inward until point C is in radial alignment with segment edgeD, and that during the next X of rotation in the same direction, radialedge D will move outward until a point G on collar 6, which is equallyas eccentric as the point E thereon, is disposed in radial alignmentwith segment edge D. A further rotation of eccentric collar 5 in thesame direction is impractical for making molds as it will obviouslyforce that portion of the outer face of the segment adjacent radial edgeD outward beyond its initial position.

The foregoing `demonstrates Ithat in the formation of annular molds themaximum permissible angle of rotation of eccentric collar B relative topattern segment 1, when the latter is in its proper mold rammingposition, is always 2X, iQe., .twice the angle enclosed between theradial lines FE and FC. The arcuate pattern segment I, when expressed interms ofthe langle included between lines FE and FC is always equal to180-X. Now, if MR@ designates the maximum angle of rotationof collar 6relative to pattern segment I, MR=2X and, if S designates the angle ofthe arcuate pattern segment I, then S=180-X, which may be writtenX=180-S. Since MR=2X it is further apparent that which is the same asMRc=36-2S. Y

Thus the maximum practical rotation of patternisegment I :can never;exceed the includedlangie-fof Lthesegment because a `:rotation of`segment Ithroughra greater angle -thanthat `aforemenmentioned willlleavea, `gap between the lagging radial edge offsegment `I :and-the adjacentend offthe moldsection :previously formed. Therefore, .nothing is to begained by .adopting an arrangement aifording a rotation fof segment I inexcess ofthe angle which is encompassed by its arcuate* surface. Infact, the laggingedge of segment II :preferably overlaps thefadjacentend of thehpreviously formed `mold section to insure the formation of amold Vhaving a flawless inner surfasce land to prevent breaking raway ofthe yadjacent Aledge of the previously formed mold during the succeedingramming operation. Consequentlygas -a practical matter,` the maximumrotationof pattern segment I (MRS) -should never exceed the angleencompassed by pattern segment I (S). VThe Amaximum pattern segmentrotation (MRS) relativetc eccentric collar 5, after the Acollar has beenrotated through its maximum angle `of rotation (MRC), `is equal to MZRCor -2X, as previously explained. This fact may -be `confirmed byobserbing that `during rota-tion of--segment I relative to collar tthrough an angle of "X" in the same direction in which collar 6was-'rotated radial edge D will move inwardly frompointG on collar 6until it is in radial alignment with `-the fpoint of minimumeccentricity C thereon, and yduring the Iensuing rotation of Xc in thesame direction, radial edge D will move outward -until it fallsin radialalignment with point E on collar 6, which is equally as eccentric aspoint thereon, and which therefore positions radial edge D initsinitially radially outward position. A further rotation of patternsegment I relative to eccentric collar 6 is impractical fonmaking moldsas it will obviously force Ithat portion of the outer face of segment I,adjacent radial edge D, outward 'beyond its proper mold formingIpositio-n.

Since MRS-42X, and since Miter-2X as proven earlier, it follows thatMRS=MRC- Now, since MRS should never exceed S as previously explained,for all `practical purposes MRS=S- This being so, 'formula MR=360e2S maybe written S=`360f-2S, or 3S=360- Solvingi'this formula,` S. MRS, and"MR-c all equal 12o".

A pattern segment of 120 is the largest which canbe advancedfrom itsinitial ramming vposition to its next renaming` position so that thefull arcuate extent or" the segment is presented in continuous moldforming relation to the previously rammed 4mold section, in only twosteps. This two stepV process is accomplished by first rotatingeccentric collar lF(120") relative to pattern segment I andthen rotatingsegment I(120) relative to collar t. Obviously a smaller pattern segmentmay be effectively used in a similar manner. In addition alargcr segmentmay be eiiectively moved `from one practical ramming position tothe'next in either `oi two ways: (1) `rotation of eccentric collar 5relative to pattern Asegment i through an -angle somewhat less than MRC,followed "by simultaneous rotation of eccentric collar 6 and patternsegment I as a uni-t, relative to the contemplated mold until the fullarcuate extent of segment I is spaced inwardly from its rammingposition, in turn followed by rotation of eccentric collar .Brelative topattern segment I in an opposite direction until the segment is movedradially outward into its ramming 'position; and `(2) rotation `ofeccentric collar 6 through an angletsomewhat ,less ythan MRc .relato'complete a meldt-with aminimum numiberf` separate ramming operations,`and yet the segment Ishouldbe small enough to be readilywithdrawablefrom the inner surface `of a mold Vsec*- tion adistance suchthatthesegment `can be easilyand quiekly-rotatedimin onerammingiposition to another withoutfcausing `damage to the previouslyformed mold section. `The positioning apparatus-of the 'presentinvention is designed `for use with patternsegments of somewhatlessfthan` 1'80",` and therefore, `itiollows that a minimumto threeseparate ramming operations must vbe executed before a complete annularmold canfbe formed therewith.

Although a pattern segment `of y'is theoretically workable, actually, toobtain va `practicalfdegree of overlap, as previously pointed out, apattern ysegment `of v120" requires four ramming'f'operations. Thefactthatthe human 'factor is involved, makes it desirable touse asegmentiless than 120 toavoid a simultaneousor step-by-'step patternshifting procedure previously described as being possible. Furthermore,thesm'allersegments are less costly to-build andf'rnorelconvenient touse. Experience in forming circular 'moldspf '7 to 8 feet in `diameterhas showna 90`-pattern segment to be of satisfactoryV utility yeventhough sucha segment requiresve `separaterarrnning operations (allowingfor overlap 'for `eachrarnming operation) in order 'to complete anannular mold.

From the Aforegoingit should be obviousto one skilled in the vart thatthe present invention 'affords a simple, economical and trouble`freeapparatusforforming molds with a unitary pattern segment and thatit may be successfully practiced with apparatus differing somewhatfromthe "practical construction. herein shown 'and described forpurposes of illustration. Accordingly'it is to be understood that theinvention is notinten'ded to belimited to the exact details ofconstruction, combination, and/or operation herein set forth, as variousmodifications `thereof, within the scope of the appended claims, mayoccur to` persons skilled in the art.

`It is claimed and desired to secured by Letters Patent:

1. An apparatus for forming a mold having an inner `arcuate faceequidistant from the center of arc thereof, said apparatus comp-rising:a spindle 'i'ixedly positionable at said center; an eccentric collar.mounted on said spindle for rotation therearoun'd, said collar havingamaximum eccentric portion; `and a pattern segment 'presentingan arcuatesurface ior forming saidface. said segment being mounted on saideccentric collar for rotation therearound and being movable in a generalradial outward direction. into a mold-forming position in response to arotation of said collar in a direction effective to move 'said maximumeccentric portion throughfan arc from a `point 4lying outside a centralangle :subtended by said arcuate surface to a point lying on-aradialline extending from saidcenterto ra terminal point of said arcuatesurface, said arc subtending at said center a second angle adjacent tsaid central angle, and said segment presenting in said mold-formingposition said arcuate surface equidistant from said center.

2. An apparatus for forming a mold having an inner arcuate faceequidistant from the center of arc thereof, said apparatus comprising; aspindle xedly positionable at said center; an eccentric collar mountedon said spindle for rotation therearound, said col'iar having a maximumeccentric portion; a hub member having a pattern segment attachedthereto presenting an arcuate surface for forming said face, saidsegment being mounted on said collar for rotation therearound and beingmovable in a general radial outward direction to place said arcuatesurface in a mold-forming position in response to a rotation of saidcollar in a direction effective to move said maximum eccentric portionthrough an arc from a rst point lying outside a central angle subtendedby said arcuate surface to a second point lying on a radial lineextending from said center to a terminal point of said arcuate surface,said arc subtending at said center a second angle adjacent to saidcentral angle, said segment presenting in said mold-forming positionsaid arcuate surface equidistant from said center; and stop means havingrelatively engageable parts, one of said parts being mounted on saidcollar and the other of said parts being mounted on said hub member,said parts `being effective upon being brought into engagement to stopsaid movement of said maximum eccentric portion beyond said second pointto prevent said .maximum eccentric portion from being interposed betweensaid spindle and said arcuate surface in the area of said central angle.

3. An apparatus for forming a mold having an Y inner arcuate faceequidistant from the center of arc thereof, said apparatus comprising: aspindle iixedly positionable at said center; an eccentric collar mountedon said spindle for rotation therearound, said collar having a maximumeccentric portion; a hub member having'a pattern segment attachedthereto presenting an. arcuate surface for forming said face, saidsegment being mounted on said collar for rotation.

therearound and being movable in a general radial outward direction toplace said surface in a mold-forming position in response to a rotationof said collar in a direction effective to move said maximum` eccentricportion through an arc from a point lying outside a central anglesubtendel by said arcuate surface to a point lying on a radial lineAextending from said center to a terminal point of said arcuate surface,said arc subtending at said center a second angle adjacent tosaidzcentral angle; and stop means having relatively engageable parts,one of said parts being mounted on said collar and the other of saidparts being mounted on said hub member, said parts being cooperativelyeffective to limit relative rotation of said collar with respect to saidhub member to prevent said maximum eccentric portion from beinginterposed between said spindle and said' arcuate surface in the area ofsaid central angle.

4. An apparatus for forming a mold having an inner arcuate faceequidistant from the center of arc thereof, said apparatus comprising: aspindle iixedly positionable at said center; an eccentric collar mountedon said spindle for rotation therearound, said collar having a maximumeccentric portion; a hub member having a pattern segment attachedthereto presenting an ar- 8 cuate surface for forming said face, saidsegment being mounted on said collar for rotation therearound andY beingmovable in a general Vradial outward direction to place said surface ina moldforming position in response to a rotation of said collar in adirection eifective to move said maximum eccentric portion through anare from a rst point lying outside a central angle subtended by saidarcuate surface and on a diametral line extending through said centerand the center of said arcuate surface to a second point lying on aradial line 'extending from said center to a terminal point of saidarcuate surface, said segment being movable in a general radial in- Warddirection to withdraw said surface from said mold-forming position inresponse to a rotation of said collar in a direction effective to movesaid maximum eccentric portion through said arc from said second pointto said first point, said arc subtending at said center a second angleadjacent to said central angle; and stop means having relativelyengageable parts, one of said parts being mounted on said collar and theother of said parts being mounted on said hub member, said parts beingeifective upon being brought into engagement in response to saidrotation of said collar to limit the maximum relative rotation of saidcollar with respect to said hub member to prevent said maximum eccentricportion from being interposed between said spindle and said arcuatesurface in the area of said central angle. 5. An apparatus for forming amold having an inner arcuate face equidistant from the center of arcthereof, said apparatus comprising: a spindie iixedly positionable atsaid center; an eccentric collar mounted on said spindle for rotationtherearound, said collar having a maximum eccentric portion; a hubmember having a pattern segment attached thereto presenting an arcuatesurface for forming said face, said segment being mounted on said collarfor rotation therearound and being movable in a general radial directionto place said surface in a mold-forming position in response to arotation'of said collar in a direction effective to move said maximumeccentric portion through an aro from a point lying outside a centralangle subtended by said arcuate surface to a point lying on a radialline extending from said center to a terminal point of said arcuatesurface, said arc subtending at Ysaid center a second angle adjacent tosaid central angle, and said segment presenting 'in said mold-formingposition said arcuate surface equidistant from said center; and stopmeans having relatively engageable parts, one of said parts beingmounted on said collar and the other of said parts being mounted on saidhub member,

said parts being effective upon being brought into engagement to limitrelative rotation of said collar with respect to said hub member to anangle of 360 degrees minus twice said central angle to prevent saidmaximum eccentric portion from being interposed between said spindle andsaid surface in the area of said central angle.

References Cited in the le Of this patent UNITED STATES PATENTS

